Rail grinding machine displaceable manually on the rails of a track

ABSTRACT

A rail grinding machine, which is displaceable manually on the rails of a track in a longitudinal direction with a machine frame supportable on a rail by way of guide rolls and a grinding apparatus mounted on the machine frame in such a way as to be pivotable about a pivoting axis running in the longitudinal direction has a grinding drive motor with a drive shaft for a grinding tool to be arranged below the drive motor, the grinding tool being drivable for rotation. A blower is arranged above the grinding tool which moves air downwardly past the drive motor and the grinding tool.

The present patent application claims priority of German utility model application No. DE 20 2017 103 078.4 the content of which is incorporated herein by reference.

The invention relates to a rail grinding machine, which is displaceable manually on the rails of a track in a longitudinal direction, the rail grinding machine comprising

-   -   a machine frame supportable on a rail by means of guide rolls,         and     -   a grinding apparatus mounted on the machine frame in such a way         as to be pivotable about a pivoting axis running in the         longitudinal direction,         -   the grinding apparatus having a grinding drive motor with a             drive shaft for a grinding tool to be arranged below the             drive motor, the grinding tool being drivable for rotation             by means of the grinding drive motor.

Rail grinding machines of this type, which are known from DE 20 2010 007 264 U1, for example, are very flexible in use and can be moved rapidly from one position to be machined to another, for example for grinding the welding beads between weld joints. As a general rule, even for manually displaceable rail grinding machines of this type, there is the requirement that they should provide a maximum grinding performance and a high grinding quality at the same time.

Therefore, the invention is based on the object of refining a rail grinding machine of the generic type in such a way as to provide an improved grinding performance as well as an improved grinding quality.

According to the invention, this object is achieved for a rail grinding machine according to the preamble of claim 1 in such a way that a blower is arranged above the grinding tool in order to move air downwardly past the drive motor and the grinding tool.

This measure ensures that the aspirated air is guided past the drive motor, causing it to be cooled to the required extent, and that this air, which is at the same time the cooling exhaust air of the motor, is then guided past the grinding tool, causing the grinding tool to be cooled as well, which results in an increased service life and, therefore, an increased grinding performance thereof. Guiding the air from the motor downwardly past the grinding tool will cause the air to strike the rail head surface such that chips and metal dust adhering thereto are removed. This increases the grinding quality, in other words the surface roughness of the ground rail head surface is reduced.

The effects achieved according to the invention are optimized in that a jacket is provided, which surrounds the drive motor and the grinding tool at least partly, with air ducts being formed between the jacket and the drive motor on the one hand and the grinding tool on the other, the air ducts being connected to the blower. This ensures that a targeted and, therefore, highly efficient air guidance past the motor and then towards the grinding tool is achieved.

According to a particularly advantageous refinement, the blower is arranged between the drive motor and the grinding tool, wherein the air duct between the drive motor and the jacket is an air intake duct while the duct between the grinding tool and the jacket is an exhaust air duct. This arrangement of the blower results in an optimized air guidance as the air flow takes place partly on the suction side of the blower and partly on the discharge side of the blower.

An optimum design of the blower is achieved if it has an impeller that is provided with a cover with a central intake opening and is coupled to the drive shaft in a co-rotational manner. When the air flows from the intake duct between the jacket and the drive motor to the central opening, the air flows through the gap between the housing of the drive motor and the cover, with the result that the drive motor is also cooled at its front end. In other words, the air intake duct is extended, between the cover and the drive motor, towards the intake opening.

An optimized air flow on the discharge side of the blower is obtained if the cover has, at its outer edge, a deflecting portion leading to the exhaust air duct. This ensures a loss-free air flow into the exhaust air duct, which in turn results in an optimized cooling of the grinding tool.

In practical application, the grinding apparatus has, in the vast majority of cases, a servo-motor arranged above the drive motor for the axial displacement of the drive shaft, which enables the grinding tool to be fed towards the rail and readjusted in the event of corresponding wear. In this regard, it is advantageous if the blower is fastened to the drive shaft in such a way that it is not displaceable axially in relation to the drive shaft. In other words, the blower is moved together with the grinding tool, causing the disk-shaped gap between the drive motor and the blower to be increased.

Further advantages, details and features of the invention will emerge from the ensuing description of an exemplary embodiment, taken in conjunction with the drawing, in which

FIG. 1 shows a side view of a manually guided rail grinding machine, and

FIG. 2 shows a vertical longitudinal section through the grinding apparatus of the grinding machine as shown in FIG. 1.

The grinding machine 1 shown in FIG. 1 for grinding in each case one rail 2 of a track has a machine frame 3, which is guided on the rail 2 via guide rolls 4. By means of a cross-beam not shown, the frame 3 is supported on the other rail (not shown) of the track as is common practice in practical application and known from DE 20 2010 007 264 U1. The machine frame 3 is provided with handles 5 allowing the grinding machine 1 to be arranged on and removed from the rail. In the machine frame 3, a grinding unit 6 is mounted such as to be pivotable about a pivot axis 7 parallel to the rail 2. This grinding unit 6 has a mounting bracket 8, which is mounted, at its ends, in pivot bearings 9 disposed on the machine frame 3, the pivot bearings 9 defining the pivot axis 7 and being supported on the rail 2 by means of sensing rollers 10. The upwardly bent mounting bracket 8 carries a grinding apparatus 11 arranged approximately in the center thereof. This grinding apparatus 11 has, at its center, an electric grinding drive motor 12 and a servo-motor 13, which is also electric, the servo-motor being arranged above said grinding drive motor 12. A grinding tool 14 configured as a cup grinding wheel is provided below the grinding drive motor 12. The drive motor 12 and the servo-motor 13 are supplied with electrical energy from an energy supply module arranged on the mentioned cross-beam, for example an electric generator, driven by means of an Otto-cycle engine, with a downstream storage battery as is common practice in practical application and known from DE 20 2010 007 264 U1. The grinding apparatus 11 is supplied with energy via a line 15. The mounting bracket 8 with the grinding apparatus 11 is pivoted manually by means of a pivot spindle drive 16.

As can be seen from FIG. 2, the grinding apparatus 11 has a housing 17, which is firmly connected to the mounting bracket 8. The drive motor 12 is arranged below the mounting bracket 8. The drive motor 12 is a so-called external rotor motor the stator 18 of which is firmly connected to the housing 17. The rotor 19, which is arranged in the housing 17 radially outside the stator 18, is connected to the drive shaft 20 for the grinding tool 14 in a non-rotational manner while the drive shaft 20, however, is displaceable in relation to the rotor 19 in the direction of its longitudinal center axis 21 forming the axis of rotation. With its inner rotor sleeve 22 that accommodates the drive shaft 20, the rotor 19 is rotatable in the stator 18 by means of roller bearings 23 but is mounted in such a way as to be non-displaceable in the direction of the longitudinal center axis 21. Between the stator 18 and the radially outer sleeve-like rotor portion 24, the stator laminations 25 are arranged.

Above the mounting bracket 8, the servo-motor 13 is arranged on the housing 17, which is capable of driving, by means of its servo-motor shaft 26, a threaded spindle 27 firmly connected thereto of a spindle nut drive 28. The threaded spindle 27 is arranged in a spindle nut 29, which moves the drive shaft 20 in the direction of the axis 21 when the servo-motor shaft 26 and, therefore, the threaded spindle 27, are being rotated, causing the grinding tool 14 to be shifted in the direction of the axis 21 as well.

On its lower side, the drive motor 12 is closed by means of a cover plate 30, which is firmly connected to the housing 17.

Between the drive motor 12 and the grinding tool 14 firmly connected to the drive shaft 20, a blower 31 is arranged, which is non-rotationally and non-displaceably connected to the drive shaft 20 and is shifted together with the drive shaft 20 in the direction of the longitudinal center axis 21 when the drive shaft 20 is being displaced. In other words, the distance between the blower 31 and the grinding tool 14 is unchangeable whereas the distance between the blower 31 and the drive motor 12 changes in the event of said axial displacements explained above.

The blower 31 has an impeller 32, which has radially extending blades 33. In the direction of the drive motor 12, the blades 33 are covered by a cover 34, which has a large central opening 35. Between the cover 34 fastened to the blades 33 and the cover plate 30 of the drive motor 12, an air gap 36 is formed, which changes its axial width when the grinding tool 14 is being shifted as explained above. The cover 34 is bent downwardly in its outer area such that a downwardly directed deflecting portion 37 is formed that guides the air towards the outer circumference 38 of the grinding tool 14.

The drive motor 12, the blower 31 and the grinding tool 14 are surrounded by a substantially cylindrical jacket 39, which defines an air intake duct 40 between the jacket 39 and the region of the housing 17 that is associated to the drive motor 12. This is adjoined by the air gap 36 so the aspirated air flows around the outer circumference and the lower side of the drive motor 12 in such a way that a corresponding cooling effect is obtained. The air is aspirated centrally through the opening 35 of the blower 31 and accelerated radially outwardly by means of the impeller 32 and discharged again in the direction of the rail 2 through an exhaust air duct 41 between the grinding tool 14 and the jacket 39. The grinding tool is cooled in this manner. Also, grinding chips disposed on the rail 2 are blown away so the grinding head is cleaned. The air flow as a whole is designated by reference numeral 42. The jacket 39 is provided with lateral protective plates 43 serving as a protection against free-flowing chips. 

1-7. (canceled)
 8. A rail grinding machine for grinding rails of a track, the grinding machine comprising: a machine frame with guide rolls for supporting said machine frame on a rail and for enabling the rail grinding machine to be manually displaced on the rail of a track in a longitudinal direction; a grinding apparatus pivotally mounted on said machine frame about a pivoting axis running in the longitudinal direction; said grinding apparatus having a grinding drive motor with a drive shaft for a grinding tool to be arranged below said drive motor, wherein said grinding tool is drivable for rotation; and a blower arranged above the grinding tool and disposed to move air downwardly past said drive motor and said grinding tool.
 9. The grinding machine according to claim 8, further comprising a jacket disposed to surround said drive motor and said grinding tool at least partly, air ducts formed between said jacket and said drive motor on one hand and said grinding tool on the other hand, said air ducts communicating with said blower.
 10. The grinding machine according to claim 9, wherein: said blower is arranged between said drive motor and said grinding tool; and said air duct between said drive motor and said jacket is an air intake duct and said duct between said grinding tool and said jacket is an exhaust air duct.
 11. The grinding machine according to claim 9, wherein said blower has an impeller, which is provided with a cover formed with a central intake opening, said impeller being coupled to said drive shaft for co-rotation therewith.
 12. The grinding machine according to claim 11, wherein said air intake duct is extended towards said intake opening radially in a direction of said drive shaft between said cover and said drive motor.
 13. The grinding machine according to claim 12, wherein said cover has a deflecting portion at an outer edge thereof, said deflecting portion leading to said exhaust air duct.
 14. The grinding machine according to claim 9, wherein: said grinding apparatus has a servo-motor arranged above said drive motor for an axial displacement of said drive shaft; and said blower is fastened to said drive shaft so as not to be displaceable axially relative to said drive shaft. 